knuckles899

iTrader: (1)

I'm starting to wonder if it makes more sense to just slow my normal driving down just so I can rip these gears (4.36) around lol. Down side of me doing this.....going the actual speed limit everywhere. ...plus side is having a monster NA V6 with a 3rd 4th gear head snapper.

CroneOne

Great thread!
I've just ordered my 4.08 gears from czp for my '07 HR. Can't wait to have this installed.
My main focus is to improve my track driving and have more juice coming out of the corners. The track I frequent tends to have corners that you come out of right at the lowest power band of 3rd gear and the long gearing takes a while to get her going after the turns. I'm hoping this will have me in the sweet spot when it's time to accelerate.

Anyway - I am seeing that most people who put in 4.08's put in the quaife LSD as well. I'm not too schooled on aftermarket LSDs.
Can you explain the benefit of doing this over the stock LSD that I have (JDM base) in terms of track performance? I'm fairly new at the game so I don't drift corners and honestly the Z seems really planted on corners anyway.

I'm just wondering why everyone puts in the quaife along with final drive. thx.

mcarther101

iTrader: (8)

People do the LSD at the same time as the gears because it's one of those things that will save you labor or labor costs if you do both at the same time. The OEM 350z LSD is viscous, it's just basically a thick fluid that isn't as bad as an open differential, but is still terrible, and inconsistent.

Your OEM LSD is affected greatly by temperature (ie if you're driving hard/drifting, it's not going to cut the mustard). Clutch type and gear type LSD are better options. IDK which is best personally I have an OEM viscous still unfortunately w/ 3.5 gears

The_Assassin

Guys what gear do you dyno in after 4.08 final drive. I just read all over the internet that it makes your numbers on the dyno lower but your car still accelerates faster. This is so confusing. Stock my hr is 273 now after gears and injen cai I will probably go and dyno again before my full exhaust in 3 weeks. I thought it wasn't suppose to show a gain or reduced numbers on the dyno?

Nabush

For the track guys : did you see an improvment in your laptimes with the 4.08 Gears ?

i created a post here for my HR, where in acceleration i see no gains..

https://my350z.com/forum/vq35hr/5921...l#post10360592

CroneOne

Hi fellow Z's

Just a quick question about TCS. After installing your 4.08's have you found the TCS slip light going off in any situation? I've been finding that when I mash the pedal in 3rd gear I get some sputter and the slip light going off.

Would the TCS system be off due to the new gearing? It's definitely not wheel spin because 1st and 2nd work fine and I can't spin in 3rd anyway. I'm not too technically informed on what the TCS uses to detect slip.

Cheers

GeminiZ

No one ever talks about the rev up DE motors with the 7k redline. Im interested in the 4.08 and 4.36 now. Where would it put me at 70mph 80mph?

Would this improve the 0-60 time by much?

Also, if i were planning on going FI with the car, I know the stock longer gears would be better but would a supercharger with a 3.7 or 3.9 gear be a bad option?

Any response will be appreciated!

NAbuilderZ33

iTrader: (1)

Hey y'all. Just introducing myself to the thread. DE Non Rev up here. Full bolts/tune, Z1 Clutch/Flywheel combo and 4.08s with Quaife LSD. Loving my NA setup. Gears make such a difference!

Toneloc

are u saying that butt dyno wise? or do you have a time slip?

Toneloc

no one talks about the 7k rev because it is pointless to rev a de that high which is 1k past its peak power...stock gearing (3.5) is best for fi...anything thing more would be no traction at all... upping gearing is to benefit na's to get in the powerband faster and run out the gear instead shifting at the end of a 1/8 or 1/4 mile...0 to 60mph most people have noted little to no changer... you are multiplying your trq by gears, no neccesirly adding power

The_Assassin

If you get in your powerband faster wouldnt that produce better 1/4 mile times

Toneloc

The physics of it technically yes... if you use 3 gears in the 1/8mile with the 4.08 now you shifting one more time then before which can pretty much break even... if you launch right you are already in the powerband... The only experience I have had with gears is putting bigger sprockets on dirtbikes and going from 3.07 in a Cherokee to 4.56 with same size tires...sure it feels faster but your shifting more which gains are minimal to a point.

I just want to see more raw facts, timeslips, and proof. Im on the fence going 3.9 or 4.08 honestly since im de and I like to cruise 80 85.

Some people say they were disappointed with gears or they saw little to now change in times 0 to 60 or 1/4 mile and others have .3 and .4 tenths shaved off

By the time I can afford fi setup my engine will be 150000miles plus...might as well extract all it can na

ACEMAN

iTrader: (29)

Hey Toneloc,

Got your PM.. Yes, the gears will help your 1\4 times. BUT, you have to know how to drive. Not everyone knows how to shift gears When i ran my car down the strip, i never left off the gas. Power shifted the whole way. My 60ft still needed work. But, these gears are awesome. Loved them. The best mod i had done to the car. The redline on the DE does or can cause a issue with the last gear change near the end of the 1/4. This is why you need a reflash to move the redline and/or change the tire size.

Hope this helps

Toneloc

How much did you end up gaining total 1/4mile? it adds 250rpm in 6th gear with the 4.08s? might be a good thing to rev higher so I slow my **** down.

I ran a 14.0 at 100mph with street tires 2.2 60ft...I don't know how de's are running low 13's... no I don't powershift

mikecowetta

i have a question for the installer. I'm doing the 4.083/cusco lsd install myself and need to know what size of washer he used on the final drive pinion . if theres any way i could get a number or a email that would be great!

Nabush

Hi guys,

For the information i switched back to stock diff (3.5) on my track HR Z.

The car performs better on the track with the stock diff...

The 4.08 was a big money drop for me, very disapointing.

ian99rt

iTrader: (12)

Stock differential (viscous I'm assuming) with 4.08 gears I can see as being pretty traction limited. 4.08 with a good lsd or atb diff shouldmake a big difference

Nabush

No, with sticky track tires, no traction problem with the 4.08 and VLSD.

The problem with the 4.08 is the lack of performance improvment, and the loss of top end at high speed

Andrew350

This MAY require its own thread but I'll post here anyway. The story follows in a sec but the short part is, the gears whine under load.

The car is '08 base(open diff) with about 50k miles. I purchased 4.08 gears, Quaife LSD, and the recommended bearing and seal kit all from Z1 motorsports around February or March of this year. Life got in the way and I was finally able to get a local transmission shop to install them just recently.

Drop car off, about a 4-5 days go by and I get a call informing me that they need to order shims because the factory shimming would bind with the new ring and pinion. Ok, makes sense. Another week goes by and I finally get the call that the car is done. Seemed like it took forever but now I have my ride back so all is well. LOVE IT!

I was told by the shop that no sort of 'break-in' period was required for gears, just to 'take it easy for a bit'. I can tell just from my morning commute and driving around the acceleration is going to be a pure joy. I let about 2 weeks/400miles go by and decided its been long enough, and I go out for a spirited drive to one of my favorite places up in the mountains close by. It takes about 60 miles to get to this short 5-6 mile beautifully paved race track up in the sticks and I go at it. Hard throttle, hard brakes, testing out the new rear end. The handling and grip the new diff gives me is insane. Worth. Every. Penny.

Towards the end of this one section of road I very rapidly start to hear this howling noise coming from the read end. Its subtle at first and then picks up rapidly. No question about it, its the gears. I baby the thing back home with a deafening howl any time throttle is applied, even lightly. No noise on coasting and deceleration.

Obviously, the car gets dropped off at the shop day after this. Unfortunately I had to drive over a 100 miles since the noise started by the time I was able to drop the thing off.

Mechanic seems to think its the pinion bearing since it was pressed on and off several times trying to get the shimming right. They ordered a new one. Fast forward 2 WEEKS to get the thing in and installed, I drive the car, same noise. Zero improvement. They pull the rear-end, pattern check it, and tell me they believe they need to move the pinion in a few thousands. Great. So you neglected to check this when you initially gave me the car back? ANOTHER 2 weeks go by and new shims are ordered, installed, and the 'pattern looks good'. They stated that they even took the diff to a drive-line shop across town and had their techs take a look at it and confirm things looked good.

So I've had the Z back in my possession now for about 2hrs. I've clocked probably 30 miles around town and there is still a howling noise. Now it HAS quieted down substantially, but the noise is still very much there under load. Its not deafening, but its loud enough to be very obnoxious at freeway speeds, and its enough to tell my sense of logic that something is wrong.

Now the questions for those in the know. From my short story, has permanent damage been done to my gearset? Without discussing what this shop can/is willing to do for me, is there any sort of warranty on these gears? From Nissan? From Z1? Could I realistically be looking at a faulty gear set since they were quiet for 400 miles before deciding to howl? Does changing the shimming as much as they did sound fishy and I found a shop that truly doesn't know what they are doing?

HALP! lol.

P.S. I'm in the Sacramento, CA area just in case I need to ditch this shop and find someone else.

ian99rt

iTrader: (12)

From the sound of it your install shop didn't set the pinion depth correct and to make matters worse did not have you follow a break in procedure. When I set my rear end up and took it for the first 5 mile drive the rear housing cover was over 200°f (IR thermometer) . When I drained the fluid after 200 miles it was def near its end of useful lubrication.

What they have done is set your gears up with the pinion too close to the ring gear, creating alot more heat then normal during break in. When you drive the car hard you probably boiled the fluid and lost lubrication.

The incorrect contact pattern also caused the gears to wear in with the incorrect pattern and will likely howl forever.

Sorry to be the bearer of bad news but I believe your in need of a new set of gears, bearings, and a shop that actually knows what they are doing.